Reducing Radon in your Home-Part 2
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In Part I of our feature article, we discussed how radon is cancer causing radioactive gas that may be a problem in your home. We also explained why testing your home for radon is the only way to know if you and your family are at risk. In Part II we will discuss what to do if you have tested and found elevated radon levels in your home. In general, the EPA recommends fixing your home if your radon level is confirmed to be 4 picocuries per liter (pCi/L) or higher. Radon levels less than 4 pCi/L still pose a risk, and in many cases may be reduced.
In dealing with a radon problem, the EPA recommends that you use a qualified contractor to fix your home. Contractors that are certified through the EPA's Radon Contractor Proficiency Program (RCP) have taken courses and passed an exam. Contractors that meet these qualifications are listed in a national RCP report and are required to carry a current RCP photo ID card and meet minimum EPA quality standards. When you choose a radon contractor it is wise to get more than one estimate, to ask for references, and to contact some of these references to ask if they are satisfied with the contractors work. Also be aware that if you have a radon professional test your home for radon, there is a potential conflict of interest if you use the same professional or company for radon reduction work.
The cost of making repairs to reduce radon depends on the characteristics of your house and other factors. Most homes can be fixed for about the same cost as having a new hot water heater installed or having the house painted. The average cost for a contractor to lower radon levels in a home is about $1,200, although this can range from $500 to about $2500.


There are several methods that a contractor can use to lower radon levels in your home. Some techniques prevent radon from entering your home while others reduce radon levels after it has entered. The EPA generally recommends methods which prevent the entry of radon.
Your contractor will perform a visual inspection of your house and design a system that considers the specific features of your home. If this inspection fails to provide enough information, the contractor will need to perform diagnostic tests. For example, a "smoke gun" can be used to find the source and direction of air movement. These sources of air flow show possible radon routes. Another type of diagnostic test is a "soil communication test". This test uses a vacuum cleaner and a smoke gun to determine how easily air can move from one point to another under the foundation.
The type of foundation that your house has will affect the kind of radon reduction system that will work best. In New Mexico, the most common foundation designs are slab-on-grade and crawlspaces. Some houses have more than one design feature. For instance, it is possible to have a slab-on-grade under part of the house and a crawlspace under the rest. In these situations a combination of radon reduction systems may be needed.
In houses that have slab-on-grade foundations, radon is usually reduced by subslab suction. Active subslab suction (also called subslab depressurization) is the most common and usually the most reliable radon reduction method. Suction pipes are inserted through the floor slab into the crushed rock or soil underneath. They also may be inserted below the concrete slab from outside the house. The number and location of suction pipes that are needed depends on how easily air can move in the crushed rock or soil under the slab, and on the strength of the radon source. Acting like a vacuum cleaner, a fan connected to the pipes draws the radon gas from below the house and releases it into the outdoor air. Passive subslab suction is the same as active subslab suction, except it relies on air currents instead of a fan to draw radon from below the house. This is generally not as effective in reducing high radon levels as active subslab suction.
In house with crawlspaces, radon levels can sometimes be lowered by ventilating the crawlspaces passively (by opening or installing vents) or actively (with the use of a fan). Crawlspace ventilation lowers indoor radon levels both by reducing the homeÕs suction on the soil and by diluting the radon beneath the house. If this approach is used, care must taken to insulate water pipes in crawl spaces against cold weather. Another effective method to reduce radon levels in crawlspaces involves covering the earth floor with a heavy plastic sheet. A vent pipe and fan are used to draw the radon from under the sheet and vent it to the out doors. This type of soil suction is called submembrane depressurization.
Other radon reduction techniques that can be used in any type of house include sealing cracks in the foundation and natural ventilation . These methods are considered to be either temporary measures, or partial solutions to be used in combination with other methods.


Compared to radon entering the home through soil, radon entering the home through water in most cases will be a small source of risk. Radon gas can enter the home through well water. It can be released into the air you breathe when water is used for showering and other household uses. Research suggests that swallowing water containing radon may pose some risk, too. Radon problems in water can be readily fixed by using one of two methods: aeration treatment or granular activated carbon (GAC) treatment. In either treatment it is important to treat the water where it enters your home (point of entry device) so that all the water will be treated.


After a radon reduction system has been installed, it is important to do a follow up radon test to determine the systemÕs effectiveness. Having an independent tester perform the test, or conducting the test yourself, will eliminate any potential conflict of interest with the contractor. In addition, systems installed by a RCP contractor must include a warning device to alert you if the system stops working properly. Make sure the contractor tests the warning device as well as explains and demonstrates how the system operates. Ask the contractor for written operating and maintenance instructions and copies of any warranties. Your radon reduction system will need some occasional maintenance including checking the fan regularly and repairing or replacing it as necessary. Maintaining your system takes little effort and keeps the radon levels in your home low.

We extend our appreciation to the U.S. Environmental Protection Agency and U.S. Department of Health for the information in this article.


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